Dramatic development of the information industry not only provides a huge market and fast-growing force for the power supply industry, but also imposes higher requirements on an installation volume, a weight, efficiency, and output dynamic performance of a power conversion apparatus, and reliability of a system thereof, and the like. “Short, small, light, and thin” is one of major development trends of a power conversion apparatus nowadays.
A magnetic core component on a circuit board of a power conversion apparatus is the largest power component among modular power supplies, which occupies more than 20-30% of a projected area and exerts a greater impact on an appearance structure of a module and a layout of a component. Therefore, people are increasingly concerned about research on a technology related to a magnetic core component and research on high density and compactness of a module.
To achieve high density and compactness, in the prior art, a discrete magnetic core inductor vertically stands on an upper surface of a substrate, a usage area of the substrate is reduced by using a three-dimensional encapsulation structure and by using a space in a vertical direction, thereby reducing an overall volume and improving power density thereof. The power conversion apparatus uses the three-dimensional encapsulation structure, where a discrete inductor is mounted on a substrate, thereby reducing a horizontal area of the substrate. A shield layer is arranged between the inductor and the substrate, achieving an objective of reducing electromagnetic interference. In this technology, an independent inductor and a corresponding shield layer are used, and meanwhile, components on the substrate are encapsulated, so that cost of the power module is high. In another prior art, a magnetic core is arranged on a substrate, and a power circuit module of an indicator is fabricated by directly plating copper on a surface of an inner ring of the annular magnetic core and winding the magnetic core around a via hole around an outer ring of the magnetic core. In this technology, a plated-through hole is arranged on the substrate, the annular magnetic core is placed in the plated-through hole, and a conductive copper layer is formed by directly plating on an inner side wall of the annular magnetic core, a winding of the inductor is formed in combination with winding with the copper wire on the surface of the substrate, and a power circuit with the embedded inductor is used. In this technology, the winding of the magnetic core travels only through the surface of the inner ring of the magnetic core. Therefore, the inductor has only one turn of wire, and an inductance value is small. In addition, because the embedment-type winding manner is used, the embedded magnetic core has a single shape, that is, an annular shape, which cannot meet a requirement during actual applications.
In conclusion, in the prior art, the power conversion apparatus uses an independent inductor and a corresponding shield layer; and meanwhile, the components on the substrate are encapsulated. As a result, the cost of the circuit board is high. In addition, in the prior art, the winding of the magnetic core travels only through the surface of the inner ring of the magnetic core. Therefore, the magnetic core has only one turn of wire, and the inductance value is small, the embedded magnetic core has a single shape, which cannot meet a requirement for large inductance during actual applications.